Question TWO
The bar-tailed godwit, Limosa lapponica baueri, or kuaka, is a wading shorebird seen on marshy estuaries and wetlands during the New Zealand summer. Populations of this species embark on some of the longest migrations known amongst migratory animals.
Bar-tailed godwits breed in Alaska, spending the non-breeding season in New Zealand and eastern Australia (see map opposite). The journey from New Zealand to Alaska – a distance of up to 13000km – is completed in two stages. It begins in March, when the birds fly to South Korea, Japan or China. Here, they spend some time on feeding grounds (called staging sites) that may be shared with other migratory species, before leaving for Alaska in May. The birds return to New Zealand in September and October, taking a direct, non-stop route over the Pacific Ocean – a flight of approximately 11000km that takes 6–10 days. This southward migration begins about one month earlier than that of other migratory species.
Before each migration begins, flocks of godwits congregate at leaving sites and feed continuously. At the time of departure, up to 45% of their body weight is fat. Adult birds accumulate more fat than juveniles. The timing of the migratory flights coincides with weather systems, in both northern and southern hemispheres, that generate favourable tail winds.
Migratory routes of bar-tailed godwits throughout the Pacific Ocean.
Discuss the biological concepts associated with the migration of the bar-tailed godwit. In your discussion, consider: • the biological mechanisms involved in the preparation for, and during the migration • the benefits and risks of migration to the birds • how this behaviour may have evolved.
Monarch Butterfly
Butterflies, as we learned in school have a two stage process of being born. First when they come out of the egg, they become caterpillars. They then shed their outer skin and start transforming themselves into a pupa (cocoon) after some two weeks, the butterfly is born in all its glory. This well known fact is a serious problem for evolutionary theory. Evolution has long claimed (in spite of this well known fact) that the process of gestation and birth recapitulates evolution. However, other insects which arose much earlier do not reproduce this way and just a few species reproduce this way (frogs also reproduce after a transformation from egg to tadpole to frog, but interestingly, almost identical looking frogs of the same genus are born as tadpoles and by skipping the tadpole stage).
The Monarch is special and a problem to evolution in another way, it is the only insect that migrates. This is not surprising since insects are fairly small and short lived. The Monarch though migrates over several generations to its Mexican breeding grounds from all over the US and finds its way back, generations later to where it came from. Scientists are saying that it has a more accurate GPS system than the US. They cannot reproduce in the winter, so they would become extinct it they did not migrate. What no one can understand is how the knowledge of the migration site and the original summer homes is passed on through multiple generations.
The bar-tailed godwit, Limosa lapponica baueri, or kuaka, is a wading shorebird seen on marshy estuaries and wetlands during the New Zealand summer. Populations of this species embark on some of the longest migrations known amongst migratory animals.
Bar-tailed godwits breed in Alaska, spending the non-breeding season in New Zealand and eastern Australia (see map opposite). The journey from New Zealand to Alaska – a distance of up to 13 000 km – is completed in two stages. It begins in March, when the birds fly to South Korea, Japan or China. Here, they spend some time on feeding grounds (called staging sites) that may be shared with other migratory species, before leaving for Alaska in May. The birds return to New Zealand in September and October, taking a direct, non-stop route over the Pacific Ocean – a flight of approximately 11 000 km that takes 6 – 10 days. This southward migration begins about one month earlier than that of other migratory species.
Before each migration begins, flocks of godwits congregate at leaving sites and feed continuously. At the time of departure, up to 45% of their body weight is fat. Adult birds accumulate more fat than juveniles. The timing of the migratory flights coincides with weather systems, in both northern and southern hemispheres, that generate favourable tail winds.
Migratory routes of bar-tailed godwits throughout the Pacific Ocean.
Discuss the biological concepts associated with the migration of the bar-tailed godwit. In your discussion, consider:
• the biological mechanisms involved in the preparation for, and during the migration
• the benefits and risks of migration to the birds
• how this behaviour may have evolved.
Monarch Butterfly
Butterflies, as we learned in school have a two stage process of being born. First when they come out of the egg, they become caterpillars. They then shed their outer skin and start transforming themselves into a pupa (cocoon) after some two weeks, the butterfly is born in all its glory. This well known fact is a serious problem for evolutionary theory. Evolution has long claimed (in spite of this well known fact) that the process of gestation and birth recapitulates evolution. However, other insects which arose much earlier do not reproduce this way and just a few species reproduce this way (frogs also reproduce after a transformation from egg to tadpole to frog, but interestingly, almost identical looking frogs of the same genus are born as tadpoles and by skipping the tadpole stage).
The Monarch is special and a problem to evolution in another way, it is the only insect that migrates. This is not surprising since insects are fairly small and short lived. The Monarch though migrates over several generations to its Mexican breeding grounds from all over the US and finds its way back, generations later to where it came from. Scientists are saying that it has a more accurate GPS system than the US. They cannot reproduce in the winter, so they would become extinct it they did not migrate. What no one can understand is how the knowledge of the migration site and the original summer homes is passed on through multiple generations.
See links below:-
Western Monarch Butterfly
MonarchButterfly
Monarch Lifecycle
Animal Facts
CNN - Monarch Guided by Sunlight Changes
Buttefly Secret Revealed
Monarch Migration Map